Lateral line pathways and connections are being studied by axonal degeneration and radioautographic methods in the clearnose skate, Raja eglantaria. Emphasis is being given to the differential efferent projections of the anterior lateral line lobe (nucleus dorsalis), posterior lateral line lobe (nucleus intermedius) and the auricle of the cerebellum. Mechanical lesions will be made in the above receptive areas for lateral line neurons and following post-operative survival times of 2-4 weeks, the brains will be fixed by perfusion and frozen sections of the brain stems processed by the Fink-Heimer technic to depict degenerating axons and terminals. Complementary experiments will be done by injecting 0.2 to 0.4 micro 1 of tritiated proline into similar lateral line areas. Seven to ten days post-operatively, the brains will be fixed by perfusion, embedded in paraffin, and the sections coated with nuclear track emulsion, exposed for 30-35 days, and developed to show the distribution of silver grains representing terminations of secondary lateral line axons.